Metal cutting flying shear



Feb. 24, 1948. E. HENSCHKER METAL CUTTING FLYING SHEARS Filed Oct. 21, 1944 3 Sheets-Sheet 1 INVENTOR,

Feb. 24,1948. E. HENSCHKER METAL CUTTING FLYING SHEARS 1944 3 Sheets-Sheet 2 Filed Oct. 21

INVENTOR. ERHARD H E SCHKER Feb. 24, 1948. E. HENSCHKER METAL CUTTING FLYING SHEARS Filed Oct. 21, 1944 3 Sheets-Sheet 3 2 w II T W L W S W kfif ow} M "II. mm m v 2 x Q INVENTOR. ERHARD HE N CHKE'R Patented Feb. 24, 1948 METAL CUTTING FLYING SHEAR Erhard Henschker, Parkstone, England, assignor to The Loewy Engineering Company Limited, London, England, a corporation of Great Britain Application October 21, 1944, Serial No. 559,859 In Great Britain October 26, 1943 Claims. 1

This invention relates to flying shears used in rolling mill installations for sub-dividing a strip or bar of hot or cold rolled material, while moving, into pieces of equal and predetermined length. When processing rolled strip, care has to be taken that such portions of the strip as are defective in quality or appearance do not find their way into the finished products. To this end, any such defective portions have to be cut from the strip before it is sub-divided. As the cut-off pieces represent waste, it is essential, particularly in the case of material which is expensive to manufacture, that as little as possible of the sound part of the strip is cut away with any defective portions.

It is obvious that the required degree of accuracy in the cutting-off portion can only be obtained when the strip is out While at rest. This entails stopping the strip each time a defective portion is removed.

It is an object of the invention to provide a metal-cutting flying shear adapted to sub-divide material into pieces of predetermined length and one which is readily convertible into a stationary shear, so that one and the same machine can be used both for sub-dividing moving strip or bar or for cutting out defective portions of strip or bar while at rest, and this with a minimum of delay in switching over from one mode of operation to the other.

The metal-cutting flying shear according to the invention is of the kind which has a rocking frame for mounting and guiding the upper and lower shear blades respectively, and, further, a rotating cam for imparting a rocking movement to such a frame. The frame maybe pivoted about a motor-driven crankshaft which serves also to rotate the aforementioned cam, and the lower blade may be mounted in a crosshead which is reciprocated by the crankshaft inside the frame.

According to the invention, a double-acting pneumatic cylinder and piston are so connected with the shear frame and with the follower of the cam that admisson of pressure fluid to one side of the piston will pull the frame in the direction of material movement and thereby urge the follower of the cam into contact with the cam during the working stroke of the frame, contact during the return stroke being maintained by the cam pressing against the follower, whilst admission of pressure fluid to the other side of the piston will push the frame in the opposite direction and and its follower, both for the working and the return stroke of the frame.

In the first of the two alternatives, the shear frame will makean oscillating movement under the control of the cam and will therefore be suitable for cutting moving material if the speed of the frame is made uniiorm and as equal as possible to that of the material, whilst in the second alternative the shear frame will be stationary so as to make the shear suitable for cutting material at a standstill.

To convert the shear according to the invention from a flying into a stationary shear, it is solely necessary, therefore, to reverse the admission of pressure fluid from one side of the pneumatic piston to the other. This can be achieved, for-instance, by a two-way valve of conventional type or by any other suitable means which can be controlled by the operator of theshear, either mechanically or electrically. Transformation of the shear from one mode of operation to the other can, therefore, be effected easily and instantaneously while a strip or bar is passing through the shear, and the flow of material through the shear, and any further handling stations behind the shear, will not be appreciably slowed down by the necessity of cutting out defective portions from the strip or bar.

The arrangement of a pneumatic cylinder and piston which urge the cam follower into contact with the cam during the working stroke of the shear frame has the additional advantage of acting as a safeguard against potential damage to the material or the shear in cases where the speed of the shear frame tends to exceed that of the material, due to inaccurate setting or for any other reason. In such cases, the speed of the frame will be slowed down by the shear blades biting into the strip against the pull exerted on the frame by the pneumatic piston. Slowing down of the shear frame movement will result in the cam follower becoming disengaged from the cam, and the movement of the shear frame will henceforth depend entirely on the speed of the strip without any interference from the cam. Thus, any danger of additional stresses in the strip, due to an excess of speed of the shear frame over that of the strip, is avoided, and'thereby also any risk of damage to the strip or to the shear. As soon as the blades have cut through the strip, the cam follower will snap back into contact with the cam under the action of the pneumatic piston.

Uniformity of speed of the shear frame during thereby interrupt the contact betweeen the cam the major part of its working stroke can be obtained by suitably shaping the cam. A close approximation of the speed of the shear frame to that of the strip can be obtained by adjusting the speed of the crankshaft in conjunction with an adjustment of the linkage system which'transmits the movement of the cam follower to the shear frame.

Means may be incorporated in the shear ac.- cording to the invention for cutting lengths of material exceeding those obtainable with con tinued operation of the. shear, these means enabling the shear to be operated at intervals corresponding to the time necessary between subsequent cuts to permit the desired lengths of material to pass through the shear.

The invention will now be describediin detail with reference to the accompanying drawings which show by way of example a metal-cutting. flying shear according to the invention.

In the drawings- Fig. l is a side elevation of a shear Fig. 2 is a front elevation partly in section Fig. 3 is another side elevation, partly in section along the line 33 of Fig. 4.

Fig. 4 is a top plan View.

The shear shown in the drawings has bearings H for a crankshaft l2. The crankshaft I2 is driven from an electric motor 13 having a speed regulator id through an electro-magnetic clutch l5 and a reduction gear comprising a pinion l6, spur wheel H, pinion l8 and spur wheel l9.

Pivotally mounted on crankshaft I2 is a frame 26 whose side members are formed by two uprights 2| and whose top member is formed by a crossbeam 22 which serves. as a carrier for the upper shear blade 23. The lower blade 24' is carried by an apron '25 supported by two connecting rods 25 adapted to be reciprocated by the action of the crankpins 21 of crankshaft 12 so as to reciprocate the apron 25 inside frame 20.

A rocking movement is imparted to the shear frame 28 by means of a cam 36 secured to the crankshaft l2 so as to rotate therewith, and by a linkage system which will be presently described in detail. Co-operating with cam 33 is a follower or roller 3! arranged at the end of an arm 32 mounted on a rocker shaft 33. Attached: to the other end of shaft 33 is a second arm 34 to which a link 35 is pivoted. Link 35 is connected to arm 36 on a second rocker shaft 31. The rocking'movement of shaft 31 is transmitted to the shear frame 2b by means of a pair of rocker arms 33 arranged at the ends of shaft 3l-and by a pair of rods 39 pivoted to pins 43 onframe 23.

For the purpose of varying the angle of. oscillation of the shear frame 20 about. the crankshaft I2, the effective length of rocker arms 38 is adjustable. To this end, the rods 39 are not directly pivoted to their respective arms 38 but to nuts ll which are adapted totravel up and down threaded spindles 42 extending insidethe arms 33. Rotation of the spindles 42' and thereby movement of the nuts M is effected through-worm wheels 43 and a common worm shaft M, universal spindle 45, horizontal spindle 46; bevel gears 41 and vertical spindle 43, having a. handwheel 4-9 mounted at a convenient height for manual operation.

Variations or the angle of oscillation of the shear frame 26 will result in a corresponding Variation of the linear speed of the frame, and for a given speed of crankshaft l2 the speed of theframe 20 may thusbe altered. Conversely, it is possible to maintain the linear speedof the frame 28 constant, irrespective of its angle of oscillation, by varying the speed of motor 13 in conjunction with a variation of the effective lengths of the rocker arms 38. Variation of the motor speed is obtained by the regulator I l whose controlmember may be directly drivenby spindle 36 which drives also the'threaded spindles 42 as described above, so that the correct setting of the motor speed in relation to the rocker arms 38 will be ensured. Lead wires 14a and lb from a suitable source of power extend from the regulator. IE to the motor. I3.

Arranged in the central vertical plane of the shear, and laterally with respect to crankshaft I2, is a pneumatic cylinder 5d having a piston 5|, piston rod 52 and a connecting rod 53 whose free: end is pivoted to a pin 54 on the frame 20 which is' co-axial with the pins 40 for rods 39. Suitable: inlet and outlet ports are provided for the admission or exhaust of pressure fluid to and from either side of piston 51. Theflow of pressure fluid is controlled by suitable means, such as a two-way valve 59 which may be actuated by the operator of theshear.v

The valve 59. may be controlled by control lever 64 to shift. the. valve from the position in which pressure fluid is. admitted to the. side of the piston near the frame 20 to the position where the pressurefluidis admittedto. the side of the piston away from the frame 20. The pressure fluid line is indicated at 62A. The communication from the valve 59' to the side of the piston nearest the frame. 2'!) is. indicated. by the line 66A and the communicationto the side of the piston away from the frame 20. is indicated by the line 61A. The exhaust is indicatedat 63.

The arrangement. of the piston. 5| relative to the shear frame. 23 is such thatif pressure fluid is admitted tothe side of. thepiston near. the. frame 23, the piston will exert a pull on the frame and at the same time. tend to urge. the. follower 3| into engagement. with cam 30., whilst admission of pressure fluidto. the opposite side of the piston willresult ina pushing force on the frame which tends to disengage the follower 3!. from the cam 33.

The rocking movement of. the. shear frame 20 is limited by two stops 5 5 and 55..

The material to be out is. fed-to. the shear through a set of pinch or feeding. rolls 5'! which may be driven from theshear motor l3 through areduction gear (notshown) with steplessvariationof the. ratio. of. reduction. Aroller table 58 is arranged. at the delivery and of the-shear. for conveying thecut-off. pieces away from. the shear.

Considering, first the case of continuousoperation of. the shear on moving. material such as. a piece. of hot or coldrolled strip or bar, the linear speed of the. shear blades 23 and 24 first so adjusted. by the More-described means. that this speed is as nearly as possible equal to that of the material. The material is.now cuteach time the blades 23 and 24 pass through the plane of feed of the material during the oscillation of the shear frame, Both the working and thereturn strokes of the-shear framearemad'e-under the control of the cam 38; the working stroke being made whilst the piston 51 urges the follower against the: cam, and the return stroke with. the cam 33; pressing against the. follower 3|- The: cam. 30' is so shaped that. the shear frame 23- will have a uniform movement; through most of its working. stroke.

With a shearof. the type described, the length of the: cutslmade; is equal-to-thespeed of material in feet per minute divided by the number of cuts per minute, a out being made at each revolution of the crankshaft. To obtain, therefore, a certain length of material, the motor I3 is set at a speed which will give the necessary number of crankshaft revolutions, and thus the number of cuts, to produce this length. At the same time, the effective lengths of the rocker arms 38 will be so adjusted that the linear speed of the blades 23 and 24 will correspond as nearly as possible to that of the moving material, uniformity of speed during the working stroke being maintained by means of the cam 30.

So long as the speed of the blades 23 and 24 corresponds to the speed of the strip, any tension between the strip and the shear which may have detrimental effects on either is obviated. Should the speed of the frame 20, however, tend to become greater than that of the strip, due to inaccurate setting of the motor or for any other reason, the frame 20 will be slowed down by the blades 23 and 24 biting into the strip against the pull exerted by the piston Owing to the consequent retardation of the shear frame 20, the contact surface of cam 30 will recede more quickly from the follower 3| than the latter is able to advance, as the speed of the follower is determined by that of the frame 20 through the intermediary of the linkage system 32 to 39. Thus, the follower 3| will interrupt its contact with the cam 30 during the working stroke of the shear so long as the drive of the shear frame tends to move the frame faster than the strip. Movement of the shear frame will now take place solely under the action of piston 5i without any interference on the part of the cam 30 at a speed determined by the strip, so that no harmfultension in the strip can occur.

The afore-described operation of the shear is of particular importance as it forms an automatic safeguard against any damage to the shear or to the material to be cut, and therefore makes the shear particularly suitable for working on thin or delicate material. On the other hand, should the strip travel faster than the shear frame 20 moves, the strip will buckle easily against the blades 23 and 2d without suffering any damage.

' For cutting lengths of material exceeding those obtainable with continuous operation of the shear, means are provided for operating the shear at intervals corresponding to the time necessary between subsequent cuts to permit the desired length of material to pass through the shear. These means may preferably comprise a control member for the electro-magnetic clutch l5 so that the latter will be operated at suitable intervals in response to the number of revolutions of the feed rolls 51. Means and apparatus suitable for this purpose are described in the pending British application No. 4,282 of 1944. As one example, referring to Fig. 4, roll 51 can have a shaft 59 connected to control box 60, box 65 having switches connecting source of power 6| to clutch l5 through leads 62, 62' at desired intervals so that motor l3 will operate the shear at intervals depending upon the material passing through rolls 5'! to the shear. Adjustment of the speed of the shear frame 20 to correspond to the speed of the material to be cut will be made in the same way for intermittent operation as has been described before in the case of continuous operation,

It is an important feature of the shear according to the invention that it may be easily transformed into a stationary shear by the provision of the pneumatic piston 5|. It is only necessary to reverse the admission and exhaust of pressure fluid in such a way that the side of the piston 5| remote from the shear frame is subjected to pressure. This will result in a pushing force on the shear frame 20, whereby the frame will be tilted over into a slightly inclined position so as to rest against the lower stop 56. By the same movement, the follower 3| becomes disengaged from cam 30 both during the working and the return stroke. Rotation of crankshaft l2 will now result solely in a reciprocating movement of 'the apron 25 and of the lower shear blade 24 without moving the shear frame 20 and the upper blade 23, or, in other words, the shear will operate as an ordinary stationary upcut shear and is thus suitable for cutting material at a standstill.

This mode of operation enables the operator of the shear to cut outany defective portions of the strip as soon as they become apparent. It is only necessary to arrest the movement of the strip by stopping the feeding rolls 51 or any other feeding means and to reverse the action of the piston 51 by reversing the admission of pressure fluid from one side of the piston 5| to the other. The shear is thus transformed from a flying into a stationary shear and is ready to operate on material at a standstill, Any defective portions can now be cut off from the strip with accuracy. When this has been completed the admission of pressure fluid is reversed again, whereby the shear is transformed back into a flying shear and the movement of the strip is started again.

The invention can be carried out in different ways from those described here and the foregoing description is given by way of example only.

What I claim is:

1. In a metal-cutting flying shear, the combination with a motor driven shaft, a frame for mounting and guiding the upper and lower shear blades respectively, said frame being further adapted to be rocked about said shaft, a cam rotating in unison with said shaft for imparting the rocking movement on to said frame, and a follower for said cam connected with said frame, of a double-acting pneumatic cylinder and piston which are so connected with said frame that admission of pressure fluid to one side of the piston will pull said frame in the direction of material movement and thereby urge said follower into contact with said cam during the working stroke of said frame, contact during the return stroke being maintained by said cam pressing against said follower, whilst admission. of pressure fluid to the other side of said piston will push said frame 'in the opposite direction and thereby interrupt the contact between said cam and said follower, both for the working and the return stroke of said frame.

2. In a metal-cutting flying shear, the combination with a motor driven shaft, a frame for mounting and guiding the upper and lower shear blades respectively, said frame being further adapted to be rocked about said shaft, a cam rotating in unison with said shaft for imparting the rocking movement on to said frame, a linkage system connected with said frame, said linkage system having one member whose effective length is adjustable for the purpose of varying the stroke of the frame, anda follower for said cam mounted on said linkage system, of a double-acting pneumatic cylinder and piston which are so connected with said frame that admission of pressure fluid to one side of the piston will pull said frame in direction; of material: movement and. thereby urge: said follower: into contact: with: said cam duringi the working and. return stroke. of said frame; contact: during the return; stroke: being maintained by said: cam pressing against. said follower; whilst admission of pressure fluid to: the other side: of said: piston will push; said frame in the oppositev direction and thereby'interrupt' the contact betweensaid. cam and. said follower both for: the working and the return stroke: of: said frame.

3:111 a metal cutting' flying; shear, the combination with. a motorrdrivencrankshaft; a, frame for mounting the upper'shear blade and. adapted to: be rocked about said crankshaft, a crosshead mounting: the lower shear blade and guided; in said frame, said crosshead being further reciprocated by said; crankshaft, of a. double-acting pneumatic cylinder and; piston. which: are. so connected with: said frame: that admissionof pressure fluid toone side of: the piston willy-pull said: frame in the direction of material movement andith'ereby urge said; follower: into contact said cam during the working stroke of saidframe, contact during the return stroke being maintained by said cam pressing against said: follower, whilst admission of pressure fluid: to the other side: of said piston will push said frame in the opposite directionv and thereby interrupt thev contactbetween said cam and said: follower both for the working and the return stroke of said frame.

4. A metal-cutting flying shear having a" motor driven shaft, a frame for mounting and guiding the upper and lower shearblades respectively and adaptedto be rocked about said shaft, a cam rotating in: unison with said shaft for imparting the rocking movement to said frame, a follower for said cam connected with said frame,a.doubleacting pneumatic cylinder and piston which are so connected with said frame that: admission of pressure fluid to one: side of: the pistorr will pull saidframe'in the direction of material movement and thereby urge said. follower into; contact with said cam during the working stroke of said; frame, contact during the; return stroke being maintained by? said camv pressing against said; folilower; Whilst, admission of; pressure? fluid to the other side: of said piston will pushsaid. frame in the: opposite direction and; thereby interrupt the contact between; said cam and: said; follow-er both for the working, and the returnstroke; of said framagand means enabling theshear. to be operated at; intervals for the purpose of cutting lengthsof. material greaten than. thoseobtainable with continued; operation of the-shear.

5:. A metal-cutting; flying shear having amotor driven. shaft,, a frame: for mounting and; guiding the upper and lower shean'blades respectively and adapted: to: be rocked about said. shaft a cam rotating in. unison with.- said shaft for imparting the rocking movement to-said frame, a follower for said cam connected withsaidframaa doubleacting pneumatic cylinder and: piston; which are so connected with said; frame; that admission of pressurev fluid: to one side of the; piston will pull said frame in.the: direction of materialmovement and thereby urge said; follower into contact. with said cam during. the working stroke of saidframe, contact during, the return stroke; being. maintained by said cam. pressing: against said: follower; whilst admission of. pressure: fluid to the other side: of said piston will push said frame in the opposite direction and; thereby interrupt the contact between said cam and; said follower: both for" the working; and the return; stroke. of said frame; and; an electric clutch. betweenv said shaft and said motor; said clutch being; controllable; to operate: said shear at. predetermined: times in accordance with. the length ofmaterial passing through; the shear;

ERHARD HENSCHKER'.

REFERENCE S CITED The following references are of' record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,9013910' Johnson Mar. 21, 1933 1,9965%? Hahn Apr. 2,- I935 2261,00? Talbot Oct. 28, 194-1 

